Vehicle electronic control system with anti-theft capability and method of controlling a vehicle engine

ABSTRACT

Unit-specific identification data (IDA, IDB) of a transmission electronic control unit ( 5 ) and an engine electronic control unit ( 4 ) are stored in memories ( 5 A,  4 A), and engine start data (DES) required for starting an engine ( 2 ) are stored in the memory ( 4 A) of the transmission electronic control unit ( 5 ). At the time of engine starting, the validity of the combination of the transmission electronic control unit ( 5 ) and the engine electronic control unit ( 4 ) is checked in the transmission electronic control unit ( 5 ) based on the identification data (IDA, IDB), and the engine start data (DES) are sent from the transmission electronic control unit ( 5 ) to the engine electronic control unit ( 4 ) in response to a request from the engine electronic control unit ( 4 ) only when validity is confirmed.

TECHNICAL FIELD

The present invention relates to a vehicle electronic control systemwith anti-theft capability and a method of controlling a vehicle engine.

BACKGROUND ART

Various proposals have been offered regarding the protection of vehiclesagainst theft Japanese Unexamined Patent Publication No. Hei8(1996)-91176, for example, teaches an arrangement in which enginecontrol means is provided that checks a key ID code against a referenceID and enables engine starting when the two are in a relationshipdefined beforehand, and the engine control means is connected withvarious drive/control means to be controlled by connectors having aunique shapes in accordance with the configuration thereof, whereby theconnectors of an engine control means of another configuration and theconnectors of the various drive/control means cannot be properlyelectrically connected.

However, this proposed system does not always function as an effectiveimmobilizer because the engine can be easily started by obtaininganother genuine engine control means whose ID code is known andreplacing the engine control means installed in the vehicle.

An object of the present invention is therefore to provide a vehicleelectronic control system with anti-theft capability and a method ofcontrolling a vehicle engine which overcome this problem of the priorart.

Another object of the present invention is to provide a method ofcontrolling a vehicle engine capable of preventing vehicle theft.

DISCLOSURE OF THE INVENTION

Many vehicles in wide use today are equipped with a micro-hybridtransmission control unit or other such automatic transmission controlsystem having an electronic control unit built into the transmission andwith an engine control system constituted to include a separateelectronic control unit for controlling the operation of the engine. Thepresent invention focuses on this fact to provide a vehicle withanti-theft capability by interconnecting the vehicle systems through anonboard LAN or the like to enable exchange of data between the systems,providing each system with its own unique identification data, utilizingthe identification data to check whether the combination of the twosystems is valid, and sending prescribed data required for enginestarting from the automatic transmission control system to the enginecontrol system only when the combination is found to be valid.

One feature of the present invention resides in the point that in avehicle electronic control system with anti-theft capability, whichincludes an automatic transmission control system having a transmissionelectronic control unit built into a transmission and an engine controlsystem constituted to comprise an engine electronic control unit forcontrolling engine operation,

unit-specific identification data are stored in each of the transmissionelectronic control unit and the engine electronic control unit foridentifying the units, engine start data required for starting theengine are stored in the transmission electronic control unit, and, atthe time of engine starting, the validity of the combination of thetransmission electronic control unit and the engine electronic controlunit is checked based on the unit-specific identification data, and theengine start data are supplied to the engine control system only whenvalidity is confirmed.

Another feature of the present invention resides in the point that in amethod of controlling a vehicle engine of a vehicle including anautomatic transmission control system having a transmission electroniccontrol unit built into a transmission and an engine control systemconstituted to comprise an engine electronic control unit forcontrolling engine operation, the method comprises, in the transmissionelectronic control unit at the time of engine starting,

a discrimination step for discriminating validity of the combinationwith the engine electronic control unit and a step of sending enginestart data required for starting the engine from the automatictransmission control system to the engine control system only whenvalidity is confirmed in the discrimination step.

Whether or not the combination of the automatic transmission controlsystem and the engine control system is valid can be established at thetime of combining these systems in individual vehicles by assigningidentification data for defining validity. By also storing theprescribed data required for starting the engine in the automatictransmission control system at this time, it becomes possible toeffectively prevent vehicle theft because even if the electronic controlunit for the engine control system is replaced with another genuineunit, the data required for starting the engine will not be sent fromthe electronic control unit of the automatic transmission control systemin this engine control system. On the other hand, since the electronicunit of the automatic transmission control system is installed insidethe transmission at the factory, it is not easy to replace, i.e.,requires a great deal of work to replace, so that the invention is veryeffective for preventing vehicle theft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overall schematic diagram showing an embodiment of thepresent invention.

FIG. 2 is a flow chart representing an engine control processing programexecuted in the CPU of the engine electronic control unit shown in FIG.1.

FIG. 3 is a flow chart representing an engine start data transmitprocessing program executed in the CPU of the transmission electroniccontrol unit.

BEST MODE OF CARRYING OUT THE INVENTION

FIG. 1 shows a vehicle system 1 equipped with a vehicle electroniccontrol system with anti-theft capability according to the presentinvention, wherein 2 designates an engine and 3 designates an automatictransmission installed on the output side of the engine 2. The engine 2is configured to be electronically controlled by an engine electroniccontrol unit 4, and the automatic transmission 3 is configured to beelectronically controlled by a transmission electronic control unit 5installed inside a casing 3A thereof. A position switch 6 mounted in theautomatic transmission 3 detects the position at which a select lever 7is set and sends a position signal SA representing the detection resultto the transmission electronic control unit 5.

Thus the vehicle system 1 includes an automatic transmission controlsystem that electronically controls the automatic transmission 3 usingthe transmission electronic control unit 5 and an engine control systemthat electronically controls the engine 2 using the engine electroniccontrol unit 4. The engine electronic control unit 4 and thetransmission electronic control unit 5 are interconnected by an onboardLAN 8 and can exchange data via the onboard LAN 8.

The engine electronic control unit 4 is constituted as a microcomputerand has a memory 4A that stores unit-specific identification data IDAfor distinguishing the engine electronic control unit 4 from otherengine electronic control units. The transmission electronic controlunit 5 is also constituted as a microcomputer and has a memory 5A thatstores unit-specific identification data IDB for distinguishing thetransmission electronic control unit 5 from other transmissionelectronic control units. The memory 5A also stores engine start dataDES that the engine electronic control unit 4 requires for starting theengine 2.

The foregoing system for electronically controlling the vehicle system 1is configured as a vehicle electronic control system with anti-theftcapability so as to function as an immobilizer. To this end, the engineelectronic control unit 4 is equipped with an immobilizer unit 9 forinputting an operator's personal identification number. Control forstarting the engine is initiated when the operator turns on a key switch10 and then inputs a prescribed personal identification number throughthe immobilizer unit 9.

FIG. 2 is a flow chart representing an engine control processing programexecuted by a CPU 4B of the engine electronic control unit 4, and FIG. 3is a flow chart representing an engine start data transmit processingprogram executed by a CPU 5B of the transmission electronic control unit5.

The engine control processing program will be explained first withreference to FIG. 2. Execution of the engine control processing programis initiated by the operator turning the key switch 10 from OFF to ON.In step S1, the immobilizer unit 9 is requested to supply personalidentification number data. Next, in step S2, it is checked whetheracquisition of the personal identification number data has beencompleted. When acquisition of the personal identification number datahas not been completed, the discrimination result in step S2 is NO andthe program returns to step S2, whereafter step S2 is repeated untilacquisition of the personal identification number data has beencompleted. When the acquisition of the personal identification numberdata has been completed owing to the input of a personal identificationnumber through the immobilizer unit 9, the discrimination result in stepS2 become YES and the program goes to step S3.

In step S3, it is checked based on the received personal identificationnumber data whether the person who input the personal identificationnumber is an authorized operator. Specifically, it is checked whetherthe input personal identification number data match or do not matchpersonal identification number data registered in the memory 4A of theengine electronic control unit 4 beforehand. When the personalidentification number data match registered personal identificationnumber data, the person is judged to be an authorized operator, so thatthe discrimination result in step S3 becomes YES and the program goes tostep S4.

In step S4, the transmission electronic control unit 5 is requested tosupply the engine start data DES. Then, in step S5, it is checkedwhether acquisition of the engine start data DES has been completed.When acquisition of the engine start data DES has not been completed,the discrimination result in step S5 is NO and step S5 is repeated untilacquisition of the engine start data DES has been completed. When theacquisition of the engine start data DES has been completed, thediscrimination result in step S5 becomes YES and the program goes tostep S6.

In step S6, the engine start data DES are used to take steps forstarting the engine, whereafter the engine control processing program isterminated.

In step S3, when it is found based on the input personal identificationnumber data that the person is not an authorized operator, thediscrimination result in step S3 becomes NO and the program goes to stepS7. In step S7, an emergency mode is implemented, such as by stoppingthe supply of power to the key switch 10, so that the key switch 10 canno longer be used for a power-on operation unless a prescribed operationis performed. The program is then terminated.

The engine start data transmit processing program will now be explainedwith reference to FIG. 3. Execution of the engine start data transmitprocessing program is also initiated upon the key switch 10 being turnedfrom OFF to ON. First, in step S11, the identification data IDA of theengine electronic control unit 4 are acquired from the memory 4A throughthe onboard LAN 8.

Next, in step S12, a check is made as to whether the identification dataIDA of the engine electronic control unit 4 and the identification dataIDB of the transmission electronic control unit 5 have already been pairmatched. When the identification data IDA and the identification dataIDB have not yet been pair matched, the discrimination result in stepS12 is NO and the program goes to step S13, in which the identificationdata IDB and identification data IDA are paired, whereafter the programis terminated. When the identification data IDA and identification dataIDB have already been pair matched, the discrimination result in stepS12 is YES and the program goes to step S14.

In step S14, it is checked whether the identification data IDA andidentification data IDB combination is valid. When not valid, thediscrimination result in step S14 is NO and the program is terminated.When the combination is valid, the discrimination result in step S14 isYES and the program goes to step S15.

In step S15, the engine start data DES are sent to the engine electroniccontrol unit 4 when requested by the engine electronic control unit 4,whereafter the program is terminated.

Owing to the foregoing configuration of the vehicle system 1, oncesomeone has switched the key switch 10 from OFF to ON, the immobilizerunit 9 prompts the person to input a personal identification number.After the person has responded by inputting a personal identificationnumber, the input personal identification number is used to checkwhether the person is an authorized operator of the vehicle.

When the person is found to be an authorized operator, the engineelectronic control unit 4 requests the transmission electronic controlunit 5 to send the engine start data DES required for starting theengine. The transmission electronic control unit 5 acquires theidentification data IDA from the engine electronic control unit 4 andchecks the validity of the combination between the identification dataIDA and its own identification data IDB, whereafter it sends the enginestart data DES to the engine electronic control unit 4 only if thecombination is found to be valid.

Therefore, if someone who does not know the personal identificationnumber should attempt to start the engine 2 by, for example, makingready a non-genuine engine electronic control unit withoutimmobilization capability and deliberately replacing the engineelectronic control unit 4 with the non-genuine engine electronic controlunit, the discrimination result in step S14 will be NO because data pairmatching between the non-genuine engine electronic control unit and thetransmission electronic control unit 5 cannot be properly completed. Theengine start data DES stored in the transmission electronic control unit5 will therefore not be sent to the non-genuine engine electroniccontrol unit, making it impossible to start the engine.

The vehicle can therefore be effectively protected against theft becausethe engine 2 cannot be started even by replacing the engine electroniccontrol unit 4 and inputting the known personal identification number ofthe replacement. Although it is possible to start the engine bysimultaneously replacing the transmission electronic control unit 5,this requires a considerable amount of labor because the transmissionelectronic control unit 5 is mounted inside the automatic transmission3. The vehicle can therefore be very effectively protected againsttheft.

As explained in the foregoing, in the present invention the transmissionelectronic control unit and the engine electronic control unit areindividually assigned identification data and the transmissionelectronic control unit is further made to retain data required forstarting the engine, the validity of the combination of the two kinds ofidentification data is checked at the time of engine starting, and thedata required for engine starting are sent to the engine electroniccontrol unit only if validity is confirmed. If someone should replaceonly one of the electronic control units, therefore, the combination ofthe two types of identification data will be found invalid, in whichcase the data required for starting the engine will not be sent to theengine electronic control unit and theft of the vehicle by replacementof an electronic control unit will be very effectively prevented.

INDUSTRIAL APPLICABILITY

As explained in the foregoing, the vehicle electronic control systemwith anti-theft capability and method of controlling a vehicle engineaccording to the present invention are useful for effectively preventingvehicle theft by replacement of an electronic control unit.

1. A vehicle electronic control system with anti-theft capability, whichincludes an automatic transmission control system having a transmissionelectronic control unit built into a transmission and an engine controlsystem constituted to comprise an engine electronic control unit forcontrolling engine operation, which vehicle electronic control systemwith anti-theft capability is characterized in that: unit-specificidentification data are stored in each of the transmission electroniccontrol unit and the engine electronic control unit for identifying theunits, engine start data required for starting the engine are stored inthe transmission electronic control unit, and, at the time of enginestarting, the validity of the combination of the transmission electroniccontrol unit and the engine electronic control unit is checked based onthe unit-specific identification data, and the engine start data aresupplied to the engine control system only when validity is confirmed.2. A method of controlling a vehicle engine of a vehicle equipped withan automatic transmission control system having a transmissionelectronic control unit built into a transmission and an engine controlsystem constituted to comprise an engine electronic control unit forcontrolling engine operation, which method of controlling a vehicleengine is characterized in that the transmission electronic control unitat the time of engine starting comprises: a discrimination step fordiscriminating validity of the combination with the engine electroniccontrol unit and a step of sending data required for starting the enginefrom the engine control system to the engine control system only whenvalidity is confirmed in the discrimination step.
 3. A method ofcontrolling a vehicle engine as claimed in claim 2, wherein thediscrimination step is a step of, in response to input of personalidentification data from an immobilizer unit, checking unit-specificidentification data assigned beforehand to the transmission electroniccontrol unit against unit-specific identification data assignedbeforehand to the engine electronic control unit.